1. Field of the Invention
The present invention relates to a ball grid array package, and more particularly, to a more particularly to a .mu.-ball grid array package with an improved structure of aligning balls.
2. Description of the Related Art
Recently, with the rapid development in a process of manufacturing an integrated circuit, a packaging technique which protects a number of unit devices formed on a unit chip from an outer environment has been progressed promptly. In most electronic units, it has been made an effort to reduce the surface area of a printed circuit board, as possible, on which a packaged semiconductor chip is mounted. In order to meet such effort, it is required that the size of a package should be smaller. As one of the techniques for miniaturizing the packaging size, Chip size package or chip scale package(CSP) which reduces the packaging size to a correspondent chip size has been proposed.
In addition, ball grid array (BGA) package, as a kind of such chip scale package, is noticed due to its excellence in performance and trust as well as the size. There are various kinds of such BGA package such as Plastic ball grid array (PBGA) package, Ceramic ball grid array (CBGA) package, Tape automated bonding ball grid array (TAB BGA) package and Ball grid array-like. Moreover, there is .mu.-ball grid array package developed in Tessera Inc.
In the above mentioned BGA packages, A signal is transferred through conductive balls from and to an external circuit. In the meantime, the more the integrity of a semiconductor chip is progressed, the more the number of the ball is increased. The increase in the number of the ball causes a short between the balls, and results in an error of data transferred through the balls. To solve the problem, it is required that the diameter of each ball should be reduced. However, it is very difficult to achieve this because of the limitation on the process.
Therefore, in all of the packages including the BGA package, it is necessary to increase the integrity without increasing the surface area which is occupied by the package.